Indianapolis Motor Speedway CEO Jeff Belskus with a 1911 Marmon Wasp that competed in the first race.

From rearview mirrors to turbochargers, devices first tried on sleek and powerful racers in the past 100 years have become part of our plainest sedans.

Here's a look at five things that were developed at the Indianapolis 500— this year's race is May 29 — and are now standard on cars.

Turbocharging

The technology, which increases an engine's power by juicing its airflow, was first tried here in 1952 on a car powered by a Cummins-built diesel engine. Driver Fred Agabashian posted the fastest qualifying time and was competitive during the race.

The technology was available on street cars — on sporty models — by the 1980s. But now, with the growing push by the government and consumers for smaller engines and better gas mileage — combined with the continued desire, by some consumers, for performance — turbos are being mainstreamed.

Chevrolet is offering them as an option on one of its low-end models, the compact Cruze. The turbo adds $2,000 to the car's $17,275 base price, yet nearly a third of the Cruzes sold are turbocharged, said David Caldwell, a Chevy spokesman. A normally aspirated Cruze comes with a 1.8-liter engine, compared with the turbo's 1.4-liter. So, while the turbo provides a livelier driving experience, its 36 mpg highway rating is the same as the non-turbo.

Turbocharged engines dominated the speedway from 1968 to 1996; then track officials banned them. They will allow them again next year.

Driver safety

In 1992, General Motors got permission from Indianapolis Motor Speedway technical director Mike Devon to outfit Indy cars with crash data recorders — battery-powered devices weighing about 4 pounds that tucked into the chassis and could measure a collision's gravity force, or G-force.

The conventional wisdom gained from aircraft and auto crash testing, some of the experiments using cadavers, was that an impact of 50 to 60 G's would be fatal, Devon said.

So he and others were astounded when driver Rick Mears walked away from a crash that registered 121 G's.

The incident led to a revolution in passenger car safety by changing the way engineers looked at a car's interior. The principle: The less a passenger is jostled, the better.

"Automakers used to think in terms of collapsible steering wheels and padded dashboards," said Don Jeffers, a Michigan-based automotive engineering consultant. "They figured if people bounced off something soft, they could be protected. They found out it was better not to bounce at all."

Jeffers credits the Mears crash for the rise of side air bags and small electric motors that tighten seat belts upon rapid deceleration.

Rearview mirrors

The rearview mirror was first used on an automobile in the very first Indy 500, in 1911. It was mounted, as an afterthought, on the hood of an Indianapolis-built single-seater called the Marmon Wasp.

The mirror was an answer to safety complaints voiced by competitors, all of whom rode with two people.

They worried that Ray Harroun, as the Wasp's sole occupant, would be a safety hazard.

Harroun, an engineer, bought a 3-by-8-inch mirror and mounted it on the car's hood. Not only did Harroun avoid crashing, he won the race.

Quickly, rearview mirrors became common as aftermarket add-ons for cars, said Wendy Metros of the Henry Ford Museum, and in 1912 they were offered as optional equipment on Chevrolets.

By 1916, rearview mirrors were standard on most passenger cars.

Seat belts

Seat belts started appearing around racetracks after World War II. They were adapted from military airplanes, where they were needed to keep pilots from falling out of their seats when being buffeted by turbulence or flying upside down.

"We'd go out and buy belts at Army surplus stores," said Devon, a longtime racing mechanic. "Those first seat belts on race cars were that Army (olive) drab."

As late as 1961, driver Parnelli Jones' rookie year, seat belts weren't mandatory at the speedway, and some drivers wouldn't wear them.

"There was thinking they'd be safer being thrown clear" in the event of a crash, Jones said. "But that thinking was going away by the time I got to Indianapolis."

Soon afterward, the speedway mandated seat belts. Not until 1965 did all U.S. automakers provide them as standard equipment for the front seats. (They'd been optional equipment on some cars since the mid-'50s.)

The much-wider and low-profile tires on today's passenger cars have everything to do with the evolution of tires in racing, said Al Speyer, executive director of Firestone Racing.

Not to get too technical, but in tire-business technology, there is a term called aspect ratio. That, in essence, is the ratio of the width of the tire to the height.

Those narrow, tall tires on the Wasp were 100% aspect ratio. But as 100 years passed, tires got wider and wider, with shorter sidewalls. "That directly has come from racing," said Speyer. The aspect ratio on race cars is now 45%. "The reason they wanted that in racing is it makes the tire much stiffer, so the tire is much more responsive to steering wheel inputs, more precise handling."

Sounds a lot safer.

"No. It really wasn't about safety," Speyer said. "Really, they wanted to go faster. It was about the competition to beat everybody."

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